The effect of trivalent iron on the properties of fluorochlorozirconate glass ceramics

Heat treating fluorochlorozirconate (FCZ) glasses precipitates nanocrystals in the glass matrix, resulting in glass ceramics that have storage phosphor properties suitable for use as a medical imaging plate. As the temperature of heat treatment rises, the resulting FCZ glass ceramic becomes more turbid as the size of the orthorhombic phase BaCl2 nanocrystals grow. This cloudiness results in scattering of the stimulating laser light, negatively affecting spatial resolution in computed radiography applications. The effect of Fe3+ on the valence state of zirconium and overall glass quality was investigated. The addition of small amounts of FeCl3 (1-2% on a molecular weight basis) to a ZBLAN glass composition allows for the precipitation of orthorhombic phase BaCl2 crystals while maintaining transparency of the glass ceramic.